Wounds, skin ulcers and sores of various types and origins require a long time to heal. This healing time results in an equally long period of suffering and a corresponding increase in the cost of medical care. Often, these conditions do not respond to conventional treatment and sometimes lead to a permanent affliction. In some cases, the condition progresses until it becomes necessary to amputate the limb, as in the case of over 35,000 diabetics annually. The danger of permanent affliction or even death is present if response to treatment is poor and gangrenous infection sets in.
Various methods of electrical nerve stimulation are in use for various therapeutic purposes, including the relief of otherwise intractable pain. In particular, electrical nerve stimulators are widely used to induce the contraction of skeletal muscle groups and for the relief of pain by blocking nerve conduction. To accomplish this, electrodes are placed near specific nerves either superficially, percutaneously, or by surgical implantation. The stimulation is accomplished by applying an electrical current to the electrodes. The current is applied in the form of a series of pulses. The duration of an individual pulse, the number of pulses in the series, the time interval of no stimulation after a stimulating pulse series, and the magnitude of the applied electrical current are, in general, variable and are adjusted by the attending physician, therapist, or patient.
In the past, various articles have been written concerning techniques for the electrical stimulation of nerve centers for the purposes of treating the human body. These articles have observed increased blood flow in ischemic areas, the elimination of Raynaud disease symptoms, and an accelerated healing of ulcers of various etiology and ulcers that had not previously responded to conventional treatment. For example, the article of Cook et al , "Vascular Disease of Extremities" New York State Journal of Medicine, March 1976, describes the electrical stimulation of the spinal cord and posterior roots. This stimulation was carried out in nine patients with varying degrees of vascular insufficiency in a limb. The electrical stimulation resulted in a striking relief of pain. The infarcted tissue was not restored, but healing was promoted. The results were geared to antidromic stimulation of C fibers in dorsal roots. In this article and in other articles, changes in circulation beyond that obtained with previous regional sympathectomy were observed and identified as the reasons for initiating and promoting healing of wounds and ulcers.
The article by Dooley et al., "Modification of Blood Flow to the Extremities by Electrical Stimulation of the Nervous System," South Medical Journal, 1976, described the sixteen patients who had electrical stimulation applied to various portions of the nervous system. Seven of the patients had transcutaneous stimulation applied over the cervical or thoracic spinal cord, peripheral nerves, or lower lumbar region. Eight patients had electrical stimulators implanted over the spinal cord in attempts to relieve intractable pain or some of the symptoms of multiple sclerosis. Another patient had electrical stimulators implanted over the C-6 dorsal roots for small artery disease. The electrical stimulation resulted in significant arterial dilatation and corresponding flow increases. Electrical stimulation applied to the ulnar nerves did not cause arterial dilatation.
The article by Meglio et al., "Pain Control and Improvement of Peripheral Blood Flow Following Epidural Spinal Cord Stimulation," Journal of Neurosurgery, 1981, taught the use of epidural spinal cord stimulation for the relief of chronic pain in arteriosclerotic patient. The healing of trophic ulcers was also observed. Hemodynamic studies showed an increase of peripheral blood flow following such stimulation.
The article by B. Kaada, "Promoted Healing of Chronic Ulceration By Transcutaneous Nerve Stimulation," VASA 1983, and by B. Kaada, "Vasodilation Induced By Transcutaneous Nerve Stimulation In Peripheral Ischemia (Raynaud's Phenomenon and Diabetic Polyneuropathy)," European Heart Journal 1982, indicated that marked and prolonged cutaneous vasodilation is produced in patients with Raynaud's Disease and diabetic polyneuropathy in response to distant, low frequency and, in this case, nontraumatic transcutaneous nerve stimulation. This stimulation promoted healing of chronic ulceration of various etiology.
The article by Tallis et al., "Spinal Cord Stimulation In Peripheral Vascular Disease," Journal of Neurology, Neurosurgery, and Psychiatry, 1983, suggested the use of spinal cord stimulation for the treatment of severe intractable symptoms of arterial disease. The electrical stimulation resulted in small increases in cutaneous and muscle blood flow. The improvements were maintained as long as spinal cord stimulation was continued.
In the article by Augustinsson et al., "Epidural Electrical Stimulation in Severe Limb Ischemia," Annals of Surgery, 1985, it was suggested that epidural spinal electrical stimulation could improve peripheral circulation in the cases of ischemic pain, skin ulcerations, and gangrene. It was found that this electrical stimulation was very promising in severe limb ischemia where reconstructive surgery was impossible or had failed. Approximately fifty percent of previously unresponsive ulcers could be healed. Only 38% of the treated patients had an amputation as compared to 90% in a comparable group of unstimulated patients.
Hotta et al. report about observations that provide some details about the mechanism behind the increase of the flow rate in the extremities in his article "Stimulation of Lumbar Sympathetic Trunk Produces Vasoconstriction of the Vasa Nervorum in the Sciatic Nerve Via .alpha.-Adrenergic Receptors in Rats", Neuroscience Letters, 1991. The unilateral electrical stimulation of the lumbar sympathetic trunk at low frequencies produced a substantial increase in the flow of blood in the vasa nervorum of the sciatic nerves in the hind legs of rats. This period of increased flow was followed by a moderate decrease of this flow in the leg on the side of stimulation while only the increase of flow was observed in the leg on the other side. The increase of flow, and only this increase, could still be observed in both legs after local sympathetic denervation. The mean arterial pressure remained elevated throughout the stimulation period in every one of the above experimental conditions. The observed increase of flow in the extremities was a passive response due to a central systemic constriction and not to peripherally located nervous responses. Thus the flow rate in the vasa nervorum, or other compromised vascular beds, can be maximized by selecting the proper frequency of stimulation, duration of stimulation, and should be further augmented by synchronisation with systolic pressure peaks.
In his extensive publication "Circulatory Response to Stimulation of Somatic Afferents", Acta. Physiol. Scandi, 1962, Johansson confirms the interpretation by Hotta by observing substantial increases of the resistance to flow, and concomitant arterial pressure rise, in the kidneys in response to afferent electrical stimulation of peripheral somatic nerves. The same observation was made by other authors (e.g., Olov Celander, "The Range of Control Exercised by the Sympathetic Adrenal System", Acta. Physiol. Scandi, 1954) for other internal organs including the observation of a frequency dependent degree of resistance elevation.
As can be seen, in the past, most physicians and manufacturers have viewed nerve stimulation as strictly nervous events in the afflicted area. These physicians and manufacturers have generally ignored the promotion of healing through increased circulation produced by 637 synchronized nerve stimulation".
It is an object of the present invention to provide a method for the acceleration of tissue healing.
It is another object of the present invention to provide a method for increasing blood flow through deprived tissues.
It is a further object of the present invention to provide a method that correlates electrical stimulation of nerves to the action of the heart or other internal or extracorporeal events.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.